LED Hacks

1886 Articles

Animating An LED Matrix Without A Microcontroller

February 9, 2011 by 20 Comments

[Konstantin] had some extra 27C256 EPROMS lying around and decided to use them to animate an 8×8 LED matrix. He’s not only using them to store data, but driving the display with them as well. The chip holds 32 kilobytes of data which equates to 4096 frames of animation. A 32 kHz clock circuit works with some ripple counters to scroll through each byte of stored data, turning on the columns while sinking the proper row. Of course current protection is a must so there is a ULN2308A darlington driver and some 2N2907 transistors at work, but you won’t find a programmable microcontroller. Neat!

Yep, you read that right. The picture above shows an EPROM chip that requires a UV light source to erase the data.

[Thanks Kopfkopfkopfaffe]

Upvote/Downvote Cards

February 8, 2011 by 11 Comments

Next time you throw together a talent show consider using these cards for up and down voting. [Frits Rincker] came up with the idea over the weekend based on the like and dislike buttons of Facebook. They consist of some foam board with LEDs in the outline of a hand. He built a switch which completes he blue circuit for the thumb’s up and a red circuit for thumb’s down by using a weight that slides freely in a channel, with a reed switch at either end. We’ve embedded the video after the break for you enjoyment.

Oh, and in case you were wondering; Hackaday likes this.

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Chroma – Mesmerizing LED Driven Fractal Display

February 7, 2011 by 15 Comments

chroma in action

A big fan of generative art, [Andrew Magill] wanted to build an LED display for his wall that constantly displayed images from the Electric Sheep project.  After discounting the possibility of generating these fractals on the fly, he settled on using prerecorded video clips gathered over a year’s time by Electric Sheep users.  With thousands of video clips in hand, he wrote some custom software that enabled him to sequence these 5-second video clips into just over 6 hours of video, which he later downsampled to fit his 24×16 pixel display.

Now that he had some impressive video put together, [Andrew] began designing the LED panels he would use to show off his creation.  After choosing TI TLC5947 drivers to control the LED arrays, he got to work on designing the PCBs, soldering in all of the components, and testing the displays.  Initial testing completed, he wrote some more custom software to direct the individual LED boards from a master controller, and mounted everything in a frosted-glass adorned picture frame.

Be sure to check out mesmerizing video of Chroma in action after the break.

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A Charlieplex Display And A Board Layout Tip

February 7, 2011 by 7 Comments

[Ben] is getting himself up to speed with microcontrollers. He jumped into the deep end by taking on this Charlieplex LED matrix build. As you can see after the break, he not only made the display work, but coded Conway’s game of life to run on the ATtiny85 that drives the device. What you see above is the prototype version that [Ben] used to make sure he had the hardware just right. He’s seeing the project through to a manufactured board and this is where the layout tip comes from. In order to make sure he had enough space for all of his components he printed out the board artwork, taped it to some Styrofoam, and then inserted all of the through-hole parts. Now he can be sure that physically the design works, we’ll keep our fingers crossed that everything is also kosher electrically.

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Microsimon

February 6, 2011 by 7 Comments

[Simoninns] is hoping to compete in the Sparkfun Microcontroller Contest with this cool little Microsimon instructible. The parts list is pretty small, at around 20 components. At the heart is a PIC 12F683 microcontroller. The whole project is very well documented with schematics, PCB layouts, code, and great pictures. This is a great project that you could put together really quickly and is a perfect introduction to charlieplexing. We find that, especially when teaching a new person, games are often a good project to learn from. The interactive and competitive nature of the finished product usually keeps people interested a little longer. You can catch a video of it after the break.

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8×8 LED Infinity Mirror

February 5, 2011 by 6 Comments

[chromationsystems] put out a couple instructibles on building infinity mirrors. One with an 8×8 array of LEDs and one with a 32 LED ring. These are very well  documented covering the construction of the mirror enclosure as well as the circuit and code. The effect is quite nice. The 8×8 array is interesting, we haven’t seen that before. These would make a fine addition to any geek cave/electronics lab. While it looks like these were basically advertisements for a product he sells, you can definitely make your own from his instructions. We like this kind of advertising.

See-through LED Display

February 3, 2011 by 10 Comments

[Ndsit] is having a party and wanted to liven up the place with some blinky lights. He’s a bit new when it comes to hobby electronics, and although we’d highly recommend inviting some resistors to participate, the LED matrix that he built is very nice. It’s 8×8, it’s big, and (as shown in the clip after the break) the lights seem to hover in midair. That’s because he didn’t use a substrate to make the display. A grid of enameled wire is strung between the four sides of the wooden frame. LEDs were gathered from a string of Christmas lights which means they’re in a holder and have insulated wires already connected. Each one was tied on at a junction point of the grid, then connected to a portion of the wire where enamel had been scraped off.

It works but there’s already one light that is out. We hope some current protection is added so that this can be used again and again.

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